To guarantee a high level of solder joint durability for soft solder die attach, a uniform bond line thickness is crucial. In addition, for high electrical performance, a low void concentration is desirable. However, ...
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ISBN:
(纸本)9781538680407
To guarantee a high level of solder joint durability for soft solder die attach, a uniform bond line thickness is crucial. In addition, for high electrical performance, a low void concentration is desirable. However, these goals arc difficult to achieve during reflow soldering. The die tilt and the formation of voids are mainly controlled by fluid forces. We develop a fluid dynamical model to better understand these mechanisms. The model is validated using experimental data. In order to use the model for design improvement, the simulation model is coupled with a genetic optimization algorithm. This arrangement can help to develop designs which lead to (a) uniform bond line thickness and (b) minimal void concentration. Furthermore, advanced search strategies act as an enabler for the generation of innovative design features. They may in turn foster the formulation of new intellectual property. To illustrate the spectrum of possible application scenarios, we show three industrial use cases.
This paper presents the simulation comparison of two Interpolated DFT frequency estimation methods in the control of a renewable energy system. The first method uses four points of the spectrum in calculations and MSD...
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ISBN:
(纸本)9781728112015
This paper presents the simulation comparison of two Interpolated DFT frequency estimation methods in the control of a renewable energy system. The first method uses four points of the spectrum in calculations and MSD (Maximum Sidelobe Decay) time windows and the second method uses three points of the spectrum and Generalized MSD time windows. simulations were performed for a modeled pure grid signal as well as signal distorted by Additive White Gaussian Noise and harmonic components in a very short estimation time. Both methods are very fast but the more accurate is the second method. The accuracy in real measurement conditions is in the order of 10(-4) Hz/Hz or 10(-3) Hz/Hz depending on the signal quality.
During the design of acceleration measuring system, the optimal choice of sensor parameters may only be made by careful analysis of both the MEMS sensor itself and the readout circuit. Therefore, a coupled electromech...
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ISBN:
(纸本)9781538680407
During the design of acceleration measuring system, the optimal choice of sensor parameters may only be made by careful analysis of both the MEMS sensor itself and the readout circuit. Therefore, a coupled electromechanical simulation is usually required. In this paper, we use such a simulation to determine the values of modulation voltage and switching frequency which ensure that the relative readout error is within acceptable limits. Three capacitive MEMS accelerometer structures are analyzed and the relative error due to the impact of electrostatic force is quantified. Based on these results, the recommendations about the optimal readout circuit parameters are given.
Signoff timing analysis is essential in order to verify the proper operation of VLSI circuits. As process technologies scale down towards nanometer regimes, the fast and accurate timing analysis of interconnects has b...
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ISBN:
(纸本)9781728112015
Signoff timing analysis is essential in order to verify the proper operation of VLSI circuits. As process technologies scale down towards nanometer regimes, the fast and accurate timing analysis of interconnects has become crucial, since interconnect delay represents an increasingly dominant portion of the overall circuit delay. It is a common view that traditional SPICE transient simulation of very large interconnect models is not feasible for full-chip timing analysis, while static Elmore-based methods can be inaccurate by orders of magnitude. Model Order Reduction (MOR) techniques are typically employed to provide a good compromise between accuracy and performance. However, all established MOR techniques result in dense system matrices that render their simulation impractical. To this end, in this paper we propose a sparsity-aware MOR methodology for the timing analysis of complex interconnects. Experimental results demonstrate that the proposed method achieves up to 30x simulation time speedups over SPICE transient simulation of the initial model, maintaining a reasonable typical accuracy of 4%.
Conductometric gas sensors based on SMO films must be heated to temperatures up to 550 degrees C in order to initiate the molecular adsorption process at the SMO film's surface. Very often platinum is used as the ...
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Conductometric gas sensors based on SMO films must be heated to temperatures up to 550 degrees C in order to initiate the molecular adsorption process at the SMO film's surface. Very often platinum is used as the microheater material. The long-term reliability of these devices are primarily associated with the mechanical stability of the micro-electro-mechanical systems (MEMS) structures used to hold the microheater suspended and thermally isolated from other integrated components, such as analog and digital circuitry. However, previous studies have shown that that electro-migration and thermo-migration phenomena could potentially exacerbate the stress build-up in platinum microheaters and contribute to their eventual failure. In this manuscript we propose a means to quantify the impact of vacancy transport on stress build-up in two novel microheater designs under electro-migration and thermo-migration phenomena. The first design is aimed at improved temperature uniformity and the second is aimed at microheater array operation, taking advantage of high temperature gradients to simultaneously provide multiple temperatures at different sensor locations. Our analysis shows that the thermo-migration force is much higher than the electro-migration force, meaning that the high thermal gradients in these devices contribute far more to vacancy transport than the atom transport induced by the electron wind. Furthermore, we calculate that our proposed designs are highly resistant to failure due to vacancy migration by calculating the mean-time-to-failure to be on the order of 1015 seconds under typical operating conditions.
To assess the propagation behavior of network worms, it is advisable to use modeling techniques. Existing models are based on deterministic approaches, which does not allow to take into account the dynamic nature of t...
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ISBN:
(纸本)9781728100531
To assess the propagation behavior of network worms, it is advisable to use modeling techniques. Existing models are based on deterministic approaches, which does not allow to take into account the dynamic nature of the development of the malware epidemic process. A multi-agent network worm propagation model has been developed, for example, the Code Red worm, which eliminates the disadvantages of deterministic analytic models. The simulation results allow you to accurately repeat the dynamics of the real behavior of the Code Red worm, and can be used to study the behavior of other network worms.
The article considers vector computation methods (bit-parallel simulation) for determining the observability of combinational logic gates. The computations produce an ODC (observability don’t care) set of all gates f...
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This work focuses in using experimental measurements to extract the aspect ratio (W/L) for Gate-Enclosed or Annular MOSFETs. All measurements and calculations are performed with an automated virtual instrumentation (V...
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ISBN:
(纸本)9781728112015
This work focuses in using experimental measurements to extract the aspect ratio (W/L) for Gate-Enclosed or Annular MOSFETs. All measurements and calculations are performed with an automated virtual instrumentation (VI) environment developed in LabVIEW. The VI was capable of extracting threshold voltage and low field mobility, needed for W/L calculation. An extraction procedure for the body effect factor is also presented. For validation purposes, extracted parameters were compared with those provided by the foundry (MOSIS) using traditional rectangular transistors. The extracted W/L was validated by comparing to Giraldo's experimental method. The SPICE BSIM 3 model parameters provided by the foundry is then modified using the extracted parameters including the aspect ratio. With this modification better simulation results were obtained. They were compared to the experimental measurements for an annular MOSFET drain voltage vs drain current characteristic curves at different gate voltages, showing an improvement of 58% when compared to the original non modified SPICE model parameters.
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